Method or apparatus for inhibiting myopia development in humans

ABSTRACT

A method of inhibiting myopia by exposing a person to a strobing or flickering light or pattern at a prescribed frequency and having a prescribed wavelength for a prescribed period.

FIELD OF THE INVENTION

This invention relates to a method and apparatus for inhibiting thedevelopment of myopia in humans.

BACKGROUND OF THE INVENTION

Myopia is a refractive eye disorder that affects a large segment of thepopulation (30% in Australia, up to 90% in Asia). In particular it ischaracterised by a normal ability to see nearby objects but a reducedability to see objects at a far distance. Thus the colloquial term forthis condition is nearsightedness or shortsightedness.

This condition can have an onset either during childhood, especiallyfrom the ages of 6 to 14 years, or young adulthood (15 to 25 years) andtypically worsens, particularly as a person grows through adulthood. Theperson's vision becomes increasingly blurry when focusing on distantobjects, requiring increasingly stronger optical correction over time.

There are various anatomical explanations for the presence of myopia.These include the eyeball developing with a greater than normal length,possibly due to developing an enlarged vitreous chamber, alternately thecornea or the lens may be too strongly powered. The most common cause isa longer than normal eye.

These developments result in the eye not needing to accommodate to focuson near objects and create a blurry image on the retina when focusing onmore distant objects. Further it is suggested that both genetic andenvironmental factors are important in myopia development with prolongednear work being associated with myopia.

Animal models have shown that abnormal visual experience can lead tomyopia. For example, translucent diffusers placed over the eyes ofanimals causes them to develop myopia.

In “Experimental Myopia in Cats Reared in Strobic illumination”(Cremieux, Orban, Duysen, Amblard and Kennedy), experiments on cats haveshown that myopia can be induced by subjecting kittens to low frequencystrobing lights (˜2 Hz) for more than 4 hours per day. This suggeststhat test subject animals can be prepared for myopia studies by exposingyoung animals to low frequency strobic illumination while they aredeveloping their vision.

A popular way to compensate for myopia is to use concave lenses, forexample in eyeglasses or contact lenses. The concave lens shifts theimage plane to be coincident with the retina and thus brings the distantobjects into clearer focus. A problem with these lenses is that they donot stop the myopia from developing and as the eye continues toelongate, stronger and stronger lenses are required and vision graduallyworsens.

Another form of correcting myopia is to operate on the cornea usingrefractive laser surgery techniques. This remedy is expensive and thelong term effects are not yet known. Furthermore this treatment is onlyavailable to adults with stabilised myopic eyes and further operationsmay be required if the refractive error changes in the future. Surgicalcorrection of the myopia can also result in a slight reduction in bestvision and does not treat the cause of the myopia (ie. an elongatedeye).

Another costly remedy is for the myopic individual to take drugs and eyedrops (for example pirenzipine) to combat the myopia. There are notcurrently any drops that are known to effectively inhibit myopiadevelopment. Once again, the long term effects of these remedies areunknown and it is a costly solution to the problem involving continualprescriptions and health risks. Further, the eye drops may include sideeffects of dilating the pupil and reducing the focusing ability of thepatient.

There is a need for a low cost, non-invasive treatment that assists inthe retardation or inhibition of the development of myopia, especiallyone that is safe for use on children during the onset of myopia.

OBJECT OF THE INVENTION

It is an object of the invention to overcome or alleviate one or more ofthe above problems or to provide the consumer with a useful commercialchoice.

DISCLOSURE OF THE INVENTION

In one form, although it need not be the only or indeed the broadestform, the invention resides in a method of inhibiting myopia developmentin a human subject including the steps of:

prescribing a frequency and exposure time of a strobing or flickeringlight or pattern to reduce the rate of myopia development for thesubject;

treating the subject with a strobing or flickering light or pattern atthe prescribed frequency and exposure time.

Preferably the treatment is repeated as required, such as daily.

Preferably, the method also includes the step of measuring the myopia ofthe subject.

By ‘inhibiting’ it is meant that the treatment reduces the advance ofexisting myopia and may prevent development of myopia if treated beforeonset.

In another form, the invention resides in a method of inhibiting myopiadevelopment in human subjects including the step of:

exposing the eyes of a subject to light flashing at a frequency in therange of 1 to 60 Hz for at least ten minutes per treatment.

Preferably the treatment occurs each day or each alternate day.

Preferably, the method includes a feedback loop for adjusting thetreatment in response to the effectiveness of the treatment in terms ofmeasured progress of the subject.

Preferably, the treatment is applied during daylight hours.

The treatment will preferably involve visible light (excludingultraviolet and infrared) and may exclude short wavelengths (bluelight).

In another form, the invention resides in an apparatus for inhibitingmyopia developments in human subjects comprising:

a strobable light;

a means of adjusting a frequency at which the light strobes;

a means of adjusting a period of time over which the light strobes; and

wherein said light strobes at a desired frequency for a desired timeperiod.

The apparatus may further comprise a feedback means of measuring myopiaand making an adjustment to the period of time and the frequency thelight strobes in response to the measured myopia.

Suitably, the apparatus operates at a frequency in the range 1 to 60 Hz.

Most preferably, the frequency used is in the range 5 to 20 Hz.

Generally the frequency used will compensate for the frequency of thebackground lighting.

Suitably, the time period will last for at least five minutes each day,or preferably ten or twenty minutes each day.

Most preferably the treatment will be applied for 5 or 10 minute periodsevery hour over a 2 to 10 hour period. 20 Generally the intensity of thelight used will compensate for the intensity of the background lighting.

Most preferably, the wavelength of the light will be about 550 nm.

Suitably the wavelength of light will be selected to compensate for thewavelength of the background light.

Preferably, the apparatus may further include a base.

Preferably the base will be in the form of eyeglass frames with thelight located near the hinge.

In another form the base will be mountable to a table.

The base may be in the form of a lamp stand.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described with reference to theaccompanying drawings in which:

FIG. 1 shows a flow diagram of the steps involved in the invention;

FIG. 2 shows a diagram of the invention mounted to a eyeglass base;

FIG. 3 shows a diagram of the invention mounted to a lamp stand base:

DETAILED DESCRIPTION OF THE DRAWINGS

The first step in treating myopia is to assess the subject for theircurrent condition. There are various means for testing myopia includingusing an opthalmoscope, refractometer, infrared retinoscopy, A scanultrasound, or flicker ERG, to test the reflection from the retina, withmyopia being diagnosed when the subject's refraction is measured to benegative (typically in the range of 0 D to −10 D), with more negativevalues representing more severe myopia. Once the subject is identifiedas myopic, the extent of myopia ran be assessed to determine the besttreatment.

Once the extent of myopia is known, the next step is to determine aspecific treatment for the subject. In particular, specific frequencyranges and durations for treatment will target the particular myopia.The optimal frequency may vary and faster progression rates may requirehigher frequencies and longer duration of treatment.

Flicker ERG may be utilised to determine the optimal flicker frequencyand/or stimulus pattern. Subjective responses of flicker perceptionand/or the critical fusion frequency may also be utilised.

Factors such as background lighting frequency, background lightingwavelength and background lighting intensity may be compensated by thestrobe light for the best results. For example, if background lightingis incandescent it has little 50 Hz flicker and provides light with awavelength in the yellow range around 600 nm, while fluorescent lightingmay have 100 Hz flicker and much higher colour temperatures, in the blueregion of the spectrum.

White light stimulates the maximum number of cone photoreceptors in theeye, as it activates the long, mid and short wavelengths. Hence themethod or apparatus will be most effective for stimulating improvedvision when the subject is exposed to white light. Thus when thebackground lighting is blue, as in halogen lighting, the appliedlighting must compensate for the lack of red and green wavelengths.Alternatively, when the background lighting is yellow, as inincandescent lighting, the compensating light must be more in theblue/green bandwidth range.

Intensity of the background lighting will also need to be consideredwhen prescribing a strobe light. The optimal intensity for treatment is1000 to 1300 lumen. Thus if the background lighting is dimmer than this,the treatment may not be as effective as the strobing light will bedistracting and visually disturbing. When the background lighting is atthe high end of this intensity range, the strobe light can be brightenedto complement it.

Additionally the frequency of the strobe light will need to becalculated to compensate for the background lighting frequency, forexample, the 50 Hz of halogen lighting or the lack of flicker inincandescent lighting. A typical frequency for the device would bewithin the range 5 to 20 HZ, but it would be possible to use frequenciesbetween 1 to 60 Hz to the same effect. The impact of strobe lighting onsubjects would need to be considered before prescribing the treatment,as it is understood epilepsy can be triggered by certain frequencies andthus the treatment may be of lesser use for a subject with epileptictendencies.

After characterising the myopia and calculating the treatmentparameters, the next step is to prescribe a device for the subject touse for treatment. For example a light emitting diode (LED) could bepositioned on a base worn on the subject's head during reading. Thediode would emit light at a particular wavelength, with a programmedfrequency, programmed illumination/dimness and programmed durationdetermined specifically for the subject.

The light emitting diode device would include means for adjusting thefrequency, illumination and duration of treatment as required for thesubject. The diodes are replaceable to provide for different wavelengthsof light for treatment as required.

Current microprocessor technology allows the production of small,application specific integrated circuits which would be suitable forproviding the required control of wavelength, intensity, pulse frequencyand pulse duration.

Another embodiment would be to use a strobe light on a base to emit thelight for treatment. Once again, this lamp would need to include a meansfor adjusting the frequency, illumination and duration of the light tobe used for treating subjects.

The base as illustrated in FIG, 2 and FIG. 3 could comprises a portablestructure such as spectacle frames (20) or other head attachments toallow the light, such as a LED (21), to be positioned close to the eyeand controlled by a microprocessor (22). Additionally the base could bea more solid structure, such as a lamp base (30), formed to rest on adesk or table during use. In this form the light source would be astrobe lamp (31) supported on the base (30) and having a control toadjust the frequency (33), on/off toggle switch (34) and an adjustabletimer (35).

The optimal delivery of the strobe treatment would be for 10 minutes perhour throughout the day. In practical application, it may also beprovided in a single duration once per day. For children at school, aneffective treatment would be during an hour of reading after school.

Although the preferred treatment delivery modality is a strobing lightas described above, other temporally modulated flickering targets may beeffective. For instance, the strobing light may be replaced by aflickering pattern on a screen, such as a computer monitor or smallhand-held display. In this embodiment the pattern is made up of a gridof lines, squares, or other shapes. The pattern has areas of lowluminance (black) and high luminance (white) which alternate at apredetermined frequency. This delivery method may be more suitable forolder children who spend a significant amount of time looking at acomputer screen. The effect is essentially the same as the strobinglight but is delivered directly from the viewing are. The Treatment maybe delivered from a small section of the screen while other programs arerunning or may be part of a separate treatment program that runs atpredetermined times.

Similarly, the treatment may be delivered from a television screen whilewatching television programs. In this embodiment a small set-top boxdelivers a television frequency signal in-line with the receivedtelevision signal. The set-top box is programmed to provide a ‘testpattern’ type signal in one corner of the screen. As with the strobinglight embodiment the ‘test pattern’ flickers at a pre-determinedfrequency for a pre-determined period of time.

The final step in the iterative process is a feedback loop, where myopiais remeasured and treatment is recalculated. The success of thetreatment will be measurable as a reduction in the myopia of thesubject. As the myopia reduces the treatment required will need to beadjusted with frequencies reduced and duration decreased. This would beachieved by adjusting the frequency and the duration.

A professional with the measurement methods described for diagnosing themyopia can perform the measurement of the myopia, at a designated timeafter treatments. Additionally a feedback mechanism can be included withthe device, which automatically adjusts the treatment. Once the reducedmyopia is measured, a new program of treatment will be calculatedconsidering new frequency and new duration required.

A feedback mechanism for automatically adjusting the treatment wouldmeasure the electrical signals from the retinal output and calculate thenew required parameters, or a subjective psychophysical equivalent couldbe used.

Treatment of subjects is measured as a reduction in the rate of growthof myopia with an expected reduction of 50%. This treatment is aniterative process with the measurements providing a feedback mechanismso the treatment can be controlled as required. At a predetermined pointof measured myopia progression, such as −0.25 D, treatment may no longerbe needed and the subject should be monitored for future regression invision.

Recent scientific experiments on animals have suggested that exposingthe eyes of test subjects to flashing lights at a certain frequenciescan cause myopia to develop. This has been useful in providing animalsubjects with myopia so that various remedies can be tested on them.This research is in conflict with the invention herein described, asflashing lights are being used to treat existing myopia rather thancause it.

As domestic lighting is commercially available in specific packagedforms, specific compensating lights can be prepared for use withlighting available in the market. For example if the background light isan incandescent 100 W globe, the compensating frequency, wavelength andluminosity can be predetermined.

It should be appreciated that various other changes and modificationsmay be made to the embodiments described without departing from thespirit or scope of the invention.

1. A method of inhibiting myopia development in a human subjectincluding the steps of: prescribing a frequency and exposure time of astrobing or flickering light or pattern to reduce the rate of myopiadevelopment for the subject; and treating the subject with a strobing orflickering light or pattern at the prescribed frequency and exposuretime.
 2. The method of claim 1 wherein the step of treating occurs eachday or each alternate day.
 3. The method of claim 1 further includingthe step of measuring the myopia of the subject.
 4. A method ofinhibiting myopia development in human subjects including the step of:exposing the eyes of a person to light flashing at a frequency in therange of 1 to 60 Hz for a selected period.
 5. The method of claim 4wherein the step of exposing occurs each day or each alternate day. 6.The method of claim 4 further including the step of selecting thewavelength of the light, the intensity of the light, the frequency offlashing and the duration of flashing.
 7. The method of claim 4 furtherincluding the step of recording feedback and using a feedback loop toadjust the treatment response to the effectiveness of the treatment interms of measured progress of the subject.
 8. The method of claim 4wherein the light flashes at a frequency in the range between 5 and 20Hz.
 9. The method of claim 4 wherein the step of exposing is applied forat least 5 minute periods every hour over a 2 to 10 hour period.
 10. Themethod of claim 4 wherein the step of exposing is applied for 10 minuteperiods every hour over a 2 to 10 hour period.
 11. The method of claim 4wherein the step of exposing is applied for at least 20 minute periodsevery hour over a 2 to 10 hour period.
 12. The method of claim 4 whereinthe step of exposing is applied during daylight hours.
 13. The method ofclaim 4 wherein the light is visible light.
 14. An apparatus forinhibiting myopia development in humans comprising: a strobable light; ameans of adjusting a frequency at which the light strobes; a means ofadjusting a period of time over which the light strobes; wherein saidlight strobes at a desired frequency for a desired time period.
 15. Theapparatus of claim 14 further comprising: a feedback means of measuringmyopia and making an adjustment to the period of time and the frequencythe light strobes in response to the measured myopia.
 16. The apparatusof claim 14 wherein the light is in the visible range.
 17. The apparatusof claim 14 further comprising means for adjusting a wavelength of saidstrobable light.
 18. The apparatus of claim 17 wherein the wavelength ofthe light is about 550 nm.
 19. The apparatus of claim 14 wherein thestrobable light operates at a frequency in the range 1 to 60 Hz.
 20. Theapparatus of claim 14 wherein the strobable light operates at afrequency in the range 5 to 20 Hz.
 21. The apparatus of claim 14 whereinthe frequency of the strobable light compensates for the frequency ofthe background lighting.
 22. The apparatus of claim 14 wherein theintensity of the strobable light compensates for the intensity of thebackground lighting.
 23. The apparatus of claim 14 wherein thewavelength of the strobable light compensates for the wavelength of thebackground light.
 24. The apparatus of claim 14 further comprising abase.
 25. The apparatus of claim 24 wherein the base is in the form ofeyeglass frames with the light located near the hinge.
 26. The apparatusof claim 24 wherein the base is mountable to actable.
 27. The apparatusof claim 24 wherein the base is in the form of a lamp stand.
 28. Anapparatus for inhibiting myopia development in humans comprising: aflickering pattern of low luminance and high luminance regions; a meansof adjusting a frequency at which the pattern flickers; and a means ofadjusting a period of time over which the pattern flickers; wherein saidpattern flickers at a desired frequency for a desired time period. 29.The apparatus of claim 28 comprising a television frequency signalgenerator that delivers a television frequency signal of the flickeringpattern.
 30. The apparatus of claim 28 comprising a computer whenprogrammed to display the flickering pattern on a monitor or screen ofsaid computer.